1. Field of the Invention
The present invention relates to filters and, more particularly, to a limiting filter in which microwave signal limiting devices have been integrally incorporated into the filter structure.
2. Description of the Prior Art
Filters are used to prevent receiver interference from out-of-band signals. Limiters are used to prevent transient rf pulses from damaging sensitive, low-noise microwave components. Currently, microwave receiver front-ends are commonly preceded by either a filter, a limiter or both. In cases where unwanted signals are out of the frequency band of the receiver filters are used to remove these signals. In cases where there are unwanted signals within the operating band of the receiver limiters can be used when the unwanted signals are at a higher level than the desired signal. In cases where there are both out of band and high level inband unwanted signals both a filter and limiter are commonly used. These two devices are normally combined in a series arrangement with the limiter following the filter. The use of two separate devices is costly and takes up unnecessary space.